1. Field of the Invention
The invention relates to a scrubbing assembly for a wafer-cleaning device; in particular, the invention relates to a scrubbing assembly with an extended lifespan and enhanced scrubbing ability.
2. Description of the Related Art
Production of semiconductor devices having microscopic structure requires high-precision technology. During processing, minute particles of dust on the circuits which constitute a semiconductor device may degrade the reliability of the finished semiconductor device. Even if dust contaminants produced during processing, which end up on a semiconductor wafer, do not adversely affect the circuit functions of the semiconductor device, they still may lead to fabrication difficulties. Therefore, the semiconductor device must be fabricated in a dirt-free environment, and the surface of the semiconductor wafer must be washed to remove minute particles of dust generated during processing.
The cleaning steps are carried out by sprinkling pure water on the wafer surface, or by allowing a rotary-fiber brush bearing a cleaning agent or pure water to contact the surface of the wafer. Scrubbing equipment is used to clean the surface of the wafer by removing dust contaminants with a brush and pure water.
Referring to FIG. 1, a conventional wafer-cleaning device 100, using DI water, is shown. Numeral 80 represents a base. Parts of the device 100 can be disposed inside the base 80. A bath 10 is disposed inside the base 80. A vacuum chuck (not shown) and a rotary shaft (not shown), connected to the vacuum chuck, are disposed inside the bath 10. A wafer 20 can be disposed on the vacuum chuck. The wafer 20, disposed on the vacuum chuck, rotates at high speed by the action of the rotary shaft.
A first arm 61 and a second arm 62 are disposed inside the base 80. A scrubber 16 is disposed at the front end of the first arm 61, and can swing along a direction, as shown by arrow E. The scrubber 16 is in contact with the wafer 20 disposed on the vacuum chuck and scrubs the surface of the wafer 20. A step motor 41, 42 and a cylinder 43, as shown in FIG. 2a, electrically connected to the scrubber 16, move and rotate the scrubber 16.
A sprayer 32 is disposed at the front end of the second arm 62. A step motor (not shown), disposed inside the second arm 62, rotates the second arm 62 and the sprayer 32 along a direction, as shown by arrow D.
A water-supplying device 30 supplies DI water to the sprayer 32. Then, the DI water, spraying from the sprayer 32, cleans the surface of the wafer 20. In the bath 10, the wafer 20, rotating at high speed, is sprayed by the DI water and scrubbed by the scrubber 16 simultaneously.
A conventional scrubbing assembly for a wafer-cleaning device is shown in FIG. 2a and FIG. 2b. The scrubber 16 connects with the first arm 61 via a third arm 65. The first step motor 41, for controlling the self-rotation of the scrubber 16, is disposed inside the third arm 65. The first arm 61 is disposed on a platform 64. A cup 50, the second step motor 42 and the cylinder 43 are disposed on the platform 64. The second step motor 42 controls the rotation of the third arm 65. The cylinder 43 controls the upward and downward movement of the third arm 65. The cup 50 receives the scrubber 16 when the scrubber 16 does not scrub the wafer 20, that is, the scrubber 16 locates in an idle position.
Referring to FIG. 2b, the scrubber 16 is provided with a body 161, a rotary shaft 162 and scrubbing bristles 163. A space 164 is formed between the body 161 and the rotary shaft 162. A tube 63, for discharging water into the space 164, is disposed at the third arm 65.
After the conventional scrubber 16 scrubs a wafer, it moves to the position beyond the cup 50 from the bath 10 by the second step motor 42. Then, the scrubber 16 moves downwardly into the cup 50 by the cylinder 43. During the downward movement of the scrubber 16, the first step motor 41 rotates the scrubber 16 itself while the tube 63 supplies water into the space 164. As a result, the scrubbing bristles 163 are cleaned by the water while it rotates.
However, since the scrubbing bristles of the scrubbing assembly are simply cleaned by the water, particles adhering to the scrubbing bristles are not easy to remove. Furthermore, since the cleaning of the scrubbing bristles is not thorough, the problem of counter-contamination between wafers may occur. In addition, concurrent procedures may be affected by the particles.
In order to address the disadvantages of the aforementioned scrubbing assembly, the invention provides a scrubbing assembly with an extended lifespan and enhanced scrubbing ability.
Accordingly, the invention provides a scrubbing assembly for a wafer-cleaning device. The wafer-cleaning device is provided with a base. The scrubbing assembly comprises a scrubber, a cup and an oscillator. The scrubber is disposed on the base in a manner such that it can move between a first position and a second position. The scrubber scrubs a wafer when it locates in the first position. The cup, for receiving DI water, is disposed on the base. The scrubber locates inside the cup and is in contact with the DI water when it locates in the second position. The oscillator is disposed at the cup, and it vibrates the DI water when the scrubber locates inside the cup and is in contact with the DI water.
Furthermore, the cup is provided with a plurality of spraying holes that spray the DI water to the scrubber when the scrubber locates inside the cup and separates from the DI water.
Furthermore, the scrubbing assembly comprises a discharging device electrically connected with the cup, and the cup is provided with a discharging hole so that the discharging device actuates the discharging holes open to discharge the DI water after the scrubber scrubs a predetermined number of the wafers.
Furthermore, the scrubbing assembly comprises a first water-supplying device and a second water-supplying device. The first water-supplying device communicates with the spraying holes so that it sprays the DI water to the scrubber through the spraying holes when the scrubber locates inside the cup and separates from the DI water. The second water-supplying device is electrically connected with the discharging device so that it can supply the DI water after the discharging device discharges the DI water from the cup.